In recent years, hybrid structures of steel and aluminum alloys have been developed for application in automobile parts, with the objective of reducing the weight of automobiles. When resistance spot welding, a method which is widely used for joining automobile bodies, is applied to the joining of steel and aluminum alloys, an intermetallic compound (IMC) layer is formed at the joint interface. It is known that the thickness of the IMC layer decreases the cross tension strength and leads to instability of the joint strength. Therefore, a resistance heating clinching combining mechanical clinching and resistance spot welding was developed. The joint strength of this technique is thought to be determined by factors such as the amount of interlock and the state of the IMC layer. However, the amount of interlock and the state of the IMC layer with a definitive effect on joint strength are not clear. In this study, the effects of interlock and the IMC layer on joint strength for the joint using resistance heating clinching were investigated. Cross tension tests were conducted on the joints fabricated using this method. The results showed that the joint strength was stable, although there were some joints where the joint strength decreased with the joint number. This is thought to have been possibly affected by changing the amount of interlock and the state of the IMC layer formation.
SHIMOKAWA et al. (Thu,) studied this question.